k & n air filters...what's your experience with them.

[dla442]

Just wanted to start a thread on the kn topic. Better mpg or worse mpg with the reusable cotton filter. I am in the process of testing them both out instead of just trusting the hype. I recently put a paper filter in place of the kn while it was cleaned, dried and oiled. I was amazed at the 12-14 to 16 mpg jump with the paper. But this could have been because I think I over oiled the kn last time given the collection of oil in the bottom of the cold air intake box washer reservoir surface. But now it's been 400 miles on paper and the 400 mile will begin on the kn that's been properly oiled.

Just looking for any GMT members experience on your kn filter investment so others can use to,their advantage whether to buy one or not.

 

[Black_tb]

i believe a lot several people are using one called green filter with some really good results way better than the k&n but im sure hardtrailz will chime in shortly

 

[HARDTRAILZ]

They get dirty on inside because particulate can flow through them so I won't use KN.

 

[DocBrown]

The amount of particulates that get through are really minimal. I have yet to read of anyone who had a motor die due to using one. I used one on my old '95 Surburban. My dad has that truck now, it stil has the K&N and it has almost 200k miles on it now. The engine is showing no signs of slowing down.

My opinion on K&N and similar filters is that on older vehicles they offer some benefit. On newer vehicles, unless you get a tune, they won't do much of anything. Even then I doubt the ROI is worth it. I've read experiences like your before, and you're mileage difference doesn't suprise me.

Personally I haven't used a K&N since my 'Burb.

 

[khill]

I've had the PCMofNC tune with a K&N CAI/Filter and I can honestly say if I were to do it all over again, I wouldn't have done it. There's quite a bit more engine noise and I don't notice enough of a performance increase to justify the price/time spent (on the CAI, the tune is great). I'm probably going to go back to stock once I can pick up the parts and just put a few more holes in the air box.

The only other thing I might try is a green filter since there's so much hype around them, but that's just more money on top of already bad money.

 

[The_Roadie]

I don't think anybody has to sacrifice an engine or suffer reduced lifetime that can't be measured or inspected for.

Just do the thought experiment: How does K&N claim more airflow without trading off filtration efficiency?

Actually "more airflow" is actually fractured physics. The airflow is the airflow. Cylinders have a fixed volume. At a specific RPM, they are going to suck exactly what capacity is in them. That's going to happen no matter what the intake is looking like. UNLESS the intake is restricted with something, be it a filter, orifice restrictor plate (like NASCAR) or poor flow through the intake plenum and the throttle body.

All the filter can do is restrict airflow and cause a pressure gradient. If you measure the pressure behind and in front of the filter, you can get an idea if it's an excessive restriction or not. The engine was designed by smart people to use paper filters, so whatever pressure differential you get with a paper filter isn't unreasonable. If a K&N has less pressure differential, it will allow a higher volume of air to flow, but the velocity is reduced. Bernoulli's Principle at work. Whether this lower velocity air is a benefit to the engine can be debated, and only a dyno test will tell for sure if it's of ANY benefit except at WOT.

I rarely use my truck at WOT< especially offroad.

But my engineering thinking is that you can ONLY obtain a lower pressure differential if the holes in the filter are larger. Oil is almost irrelevant. The pores are larger, more grit MUST be getting through, and for me (and Kyle and others) the possible cost is not worth the possible benefit.

I had one for a year and took it out as soon as I critically examined the hype and read other analyses. It's all about cost/benefit. Risk/reward. YMMV.

 

[dmanns67]

I initially had a K&N filter until doing some more research and seeing posts on this site. I came across HardTrailz's thread on the green filter from Green Filter USA and I was sold. Made the change over from K&N to Green a few months back.

 

[dla442]

So to me the green filter is just that..a green k&n filter. Still needs cleaning, oiling and claims the old horsepower, airflow and mpg increase game. So far it seems to be a Chevy v ford is better battle(ofcourseChevy wins) when it comes to paper vs the reusable filters on claims of mpg etc. been doing a lot of online feedback reading, some of the positives of the kn filter look to be corporate stooges blogging but it sure seems 50/50 otherwise. My 400 mile experiment will be done soon.

 

[HARDTRAILZ]

So to me the green filter is just that..a green k&n filter. Still needs cleaning, oiling and claims the old horsepower, airflow and mpg increase game. So far it seems to be a Chevy v ford is better battle(ofcourseChevy wins) when it comes to paper vs the reusable filters on claims of mpg etc. been doing a lot of online feedback reading, some of the positives of the kn filter look to be corporate stooges blogging but it sure seems 50/50 otherwise. My 400 mile experiment will be done soon.

http://gmtnation.com/forums/topic/155-green-filter-experience/

I have owned both. The inside of a KN is filthy quickly and every time(engine gets the dirt then). That thread shows the Green looks brand new still. At this point...it still does.

I figure I have saved well over $100 by using the washable filter. Probably more with the amount of filters that wheeling would ruin in one day. Our paper filters are not real cheap. I an also sure a paper filter would not have held up that day and a new motor may have been required.

I could two shits about mpg or HP from it. I do believe it has to flow good since I can run 16+ MPG with 35 inch tires.

 

[dla442]

Dilemma for sure. But I guess the test will reveal my winner for our TB. It was 50 bucks for my filter and have spent about 20 on cleaning kits for both cars. If the kn drops my mpg, I will switch back to paper as I don't expect keeping the TB for five more years unless I hand it down to my daughter

 

[IllogicTC]

...more airflow without trading off filtration efficiency?

Easy, if trying to fit the filter in the same-size box as before isn't an issue. Make a paper filter just like OEM, except have a lot more surface area available. That's the solution that wouldn't make you make compromises. It'd be nice to see a company doing "oversize" filters. As it is, that's the whole idea behind pleated filters anyway. Just needs taken to the next level.

 

[HARDTRAILZ]

Notice number of pleats in my green filter.

 

[BrianF]

I ran one for a year or so on my 2011 Ram. I bought it more for the fact that it may be the last filter I get for it. Well perhaps it is just me but my oil turned black real fast. I mean 3000km into the oil change I was getting real worried. I was thinking the Napa Gold was letting go. I have a 6 mile drive on grid roads from the highway one way and that gets dusty at times. I switched back to a paper element and now my oil stays golden much longer. Was it a waste of money? meh I got a good deal on it from a friend but it hasnt been used in over a year and counting. I stops dust real good sitting on the shelf.

 

[ahabofthepequod]

I have used K & N in my trucks & motorcycles since 1980. I've never experienced any issue with them and never had any engine problems as a result of using them.